Impact of Microhabitat Selection on Burrow Distribution of Nine-Banded Armadillos and Gopher Tortoises in a Pine Plantation
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Authors
Bhandari, Namrata
Issue Date
2019-07
Type
Thesis
Language
en_US
Keywords
Academic theses , Burrowing animals , Gopher tortoise , Habitat (Ecology) , Niche (Ecology) , Nine-banded armadillo
Alternative Title
Abstract
Nine-banded armadillos and gopher tortoises cohabit pine forests in the southeastern United States but may compete for burrowing locations. This may be problematic because gopher tortoises are a declining species. To examine coexistence, a microhabitat selection study was carried out at Moody Air Force Base near Valdosta, Georgia. In addition, preference of habitat parameters was compared between burrow categories, such as armadillo burrow types based on location and gopher tortoise burrow types based on age of occupant. Eighty-six burrows were randomly selected and a discriminant analyses was used to identify parameters that differentiate the locations of both species’ burrows from each other and from random sites (N = 250). Armadillo burrows (N = 40) were found in areas with higher vegetation density, greater canopy cover, steeper slopes and thicker ground cover than gopher tortoise burrows (N = 46).
Steeper slopes, low visibility and farther distance from edges separated armadillo burrows from random sites. Armadillo prefer to build burrows on berms that have steeper slopes, higher vegetation density, higher ground cover, less sunlight and lower elevation than off berm burrows. In addition to the microhabitat study, I determined the detectability of different types of burrows by comparing burrow surveys conducted prior to and after a prescribed burn. Gopher tortoise juvenile and hatchling burrows and those of armadillos off berm had low detectability during the pre-burn survey. Adult gopher tortoise burrows had higher visibility than other burrow categories. This is the first study to provide evidence that synoptic armadillos and gopher tortoises prefer to build burrows in different microhabitats. This spatial niche partitioning was probably related to their physiology.
Competition may be occurring because of the presence of coopted burrows and might suggest a complex or mixed mechanism to explain coexistence.
Keyword 1: Nine-banded armadillos
Keyword 2: Gopher tortoise
Keyword 3: burrows
Keyword 4: microhabitat
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This dissertation is protected by the Copyright Laws of the United States (Public Law 94-553, revised in 1976). Consistent with fair use as defined in the Copyright Laws, brief quotations from this material are allowed with proper acknowledgement. Use of the materials for financial gain with the author's expressed written permissions is not allowed.